The proposed invention is pertinent to the technology and equipment for the treatment of fresh fish and can be applied in the branches of fish industry, in the sphere of marketing and public catering.
To the present day a technology and, consequently, a machine do not exist that would allow to combine together the process of high-quality scaling of fish and the process of removing internal organs, to bring these processes together in time, and thus create possibility of combining these two usually separate operations into one, which substantially improves consumer qualities of goods. The given invention offers a new method for fish scaling and removal of internal organs, as well as a machine for its implementation and is directed just at elimination of the above-indicated deficiency.
Known are various methods and devices for fish scaling, for the removal of internal organs but alternately, on various machines and by different methods.
So, for scaling most often the brushes rotating at different angles to the fish surface are used as a tool (U.S. Pat. Nos. 5197916, 5184973), which is made from various materials. Relatively successfully this method can be used for scaling frozen fish. When treating fresh fish, its skin can be damaged, thin and fine tissues of abdominal cavity can be ruptured or internal organs can badly traumatized which results in upsetting gustatory properties.
Therefore, for scaling fresh fish these methods are not applied in order to preserve gustatory properties.
With the aim of more qualitative scaling, a patent of Japan has been offered (JP No. 6339336), where it is proposed to use a compressed air jet for that.
This method cannot have wide application in connection with a substantial rise in price of technology, owing to the usage of powerful compressors and the most expensive type of energy i.e. compressed air.
Inventions are available offering to use water jets under high pressure for scaling fish.
For example, Japanese Patent JP No. 4228023 offers to remove scale by means of water jets through elongated rectilinear slits with their length exceeding the maximum width of the treated fish. In this case the author offers, in order to maintain gustatory properties, to remove entrails in advance, on another machine, since the existing methods and devices for a conveyer transportation of fish in the course of scaling do not provide for safety of fish internal organs.
JP No. 4228023 which applies water jets under high pressure as a tool for scaling is closest to our invention, since it can offer the highest quality of treatment. However, the Japanese ""023 patent indicated above does not use all the potentialities of the fishscaling method by means of water jets. So, the method proposed by the Japanese ""023 patent infers such a sequence of operations, which does not provide for a satisfactory quality of scaling.
Firstly, the Japanese devices anticipates removing entrails prior to scaling. In this case it is practically impossible the cut fish belly to be scaled with a water jet, due to loss of elasticity and resistivity of these parts of the body.
Secondly, the elongated rectilinear nozzle shape offered by the Japanese ""023 patent also will not provide for scaling quality because various parts of the fish body require different modes of operation with water jets (different angles of jet inclination, different distances from the nozzle to the surface to be treated etc.) in the course of treatment. Under the conditions when throughout the whole fish width the jet supplied from one nozzle is operating, it is not possible to provide for a reliable and high-quality scaling on all portions of the fish body.
Thirdly, the method of fixing and moving the fish in the process of treatment of the Japanese ""023 patent does not allow protecting the fish belly from being squeezed by the transportation elements and, as a result, cannot guarantee retention of gustatory properties. Therefore the Japanese patent would be forced to offer to scale the entrails.
But in the Japanese ""023 patent no satisfactory method of fixing and transportation of the fish is available. Not a single one out of the considered patents solves this problem. Basically, the fish is secured and moved flatwise (patents of U.S. Pat. Nos. 5628680, 5197916, patents of Japan JP 4228023, JP 4837898) or on its back, with belly upwards (patents of U.S. Pat. Nos. 4091506, 4837898). Due to different width of the treated fish and with the transportation mechanism width being constant, some cases may occur when the fish belly is oversqueezed by the mechanisms.
So, if the fish is moving flatwise, then in case there is some fish of small width, the holding and transportation elements oversqueeze the belly damaging or destroying those entrails that can deteriorate the gustatory properties.
The same happens in those cases when the fish is held and transported with belly up basing on its back. Thus, though the prototype method and device according to patent JP 4228023 use high-pressure water jets for the fish scaling, just the same it has very essential drawbacks noted above.
Consequently, we can draw the conclusion that for the time being no method or machine are available where the fish scaling and removal of its entrails could be performed together, in one operation, using water jets. Since no method of reliable, qualitative and productive fish scaling is known, the removal of the entrails is performed on separate machines and devices, and very often it is done in combination with high pressure water jets (patents of U.S. Pat. Nos. 4837898,4535509, WO 9812929). These separate operations are performed prior to the fish scaling and very often they are even left to be done by the customer.
The method of the present invention of scaling fresh fish by means of the high pressure water jets is free from the above listed drawbacks, and allows to create a high-quality treatment technology and machine for fish scaling and entrails removal. Distinctive features and essence of the present method comprise the following:
a. Fish scaling and removal of internal organs from abdominal cavity using high-pressure water jets is performed by placing the fish vertically, with the belly downwards. In so doing and for holding and displacing the fish, the forces are applied to the upper part of its body, which is harder, without touching the belly area, which is left free. It is attained by that: prior to the fish treatment, it is based to the lower surface of the belly with respect to some reference surface A (FIG. 1) and clamping and transportation elements are located at some distance H1sufficient for that even with the maximum fish width (H2=max.) the area of the belly would not touch the clamping device. In this case this condition is also met for smaller fish. Such a system of the fish basing in the course of the treatment process allows avoiding traumatizing its internal organs and retaining gustatory properties irrespective of the treated and transported fish size.
b. The most rational sequence of technological transitions is offered: in the beginning, the whole fish surface is scaled and then the belly is cut and internal organs removed including kidneys (the so called xe2x80x9cblood spotsxe2x80x9d). By the application of this sequence of operations, the quality of the abdomen cavity scaling is improved (as compared with the prototype) when the fish is supplied for scaling in disemboweled condition. After scaling, the belly surface loses elastic properties and practically is not susceptible to scaling.
c. The scaling is done throughout the whole width of the fish surface not simultaneously but in turn, by separate zones (selectively). This distinctive feature of the method is explained by that various zones of the fish surface have different size of scale and different adhesive forces with the skin. Therefore the offered method provides for the treatment of various sections of the fish surface by means of the nozzles located at different inclinations to the fish body surface and located at various distances from the treated surface sections. In this case a geometry of the nozzle chosen is such as to provide for a flat fan-shaped jet. Owing to this, the fish scaling quality substantially increases in comparison with the known analogues and the prototype.
d. After scaling, the fish is supplied to the site for removing internal organs and is oriented in such a way, that the fish body is centered precisely with respect to the knife cutting edge axis (FIG. 2a). In this case the upper part of the cutting edge is always placed at a preset distance h from base surface A of the transportation system (FIG. 2a,b). This kind of technology of the fish basing before removing the entrails allows to improve substantially the cleaning properties of the internal cavity owing to the fact that the cutting edge can be precisely set up with respect to the lower part of the body reasoning from that the thickness of that part of the body which is necessarily to be cut. In so doing, the knife is set up so that, on the one hand, under no circumstances the cutting edge should damage those fish organs which could cause change in its gustatory properties and, on the other hand, would provide the mandatory cutting of the fish anus where a part of the entrails is held. Besides, the cleaning quality of the internal abdominal cavity increases due to the fact that while cutting with the belly being downwards, an additional possibility emerges for better removal of the entrails and washing of the abdominal cavity owing to ordinary gravitation. In this case the probability of some remains of the removed organs and dirty liquid being held up in the internal cavity sharply decreases.
On the basis of the above stated distinctive features of the new technology for the fish cleaning, a new method of cleaning and a machine for this technology implementation are offered.